Methods and apparatus to adjust bleed ports on an aircraft engine

ABSTRACT

An example method to extract bleed air from an aircraft engine includes extracting, via a plenum positioned in a compressor of the aircraft engine, bleed air from a first bleed port associated with a first stage of a compressor and a second bleed port associated with a second stage of the compressor. The plenum is configured to combine the extracted bleed air from the first and second bleed ports and fluidly couple the extracted bleed air to one or more systems of an aircraft. The method includes regulating a pressure of the extracted bleed air in the plenum by adjusting a flow of bleed air through the first bleed port via a first valve associated with the first bleed port and adjusting a flow of bleed air through the second port via a second valve associated with the second bleed port.

RELATED APPLICATION

This patent arises from a continuation of U.S. patent application Ser.No. 14/189,846, filed Feb. 25, 2014, which claims priority to U.S.Provisional Patent Application No. 61/891,283, filed Oct. 15, 2013. BothU.S. patent application Ser. No. 14/189,846 and U.S. Provisional PatentApplication No. 61/891,283 are hereby incorporated herein by referencein their entireties.

BACKGROUND

Aircraft typically include at least one power plant, such as a gasturbine. A turbofan engine is a type of a gas turbine that includes aninlet at a forward portion of the engine for providing air to the fanand compressor portion of the engine. The compressor may be amulti-stage compressor. Air is compressed in the compressor and thecompressed air passes into a combustion chamber where it is combustedwith fuel and used to drive the turbine portion of the engine. Afterpassing through the turbine portion, the exhaust is passed through anozzle located at the aft portion of the engine. Some turbofan enginesmay include two compressors (e.g., a low-pressure compressor and ahigh-pressure compressor) each driven independently by two differentshafts coupled to two different turbines.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an aircraft including an engine with an example adjustablebleed stage apparatus according to the examples disclosed herein.

FIG. 2 shows an example turbofan engine including an example adjustablebleed port selection mechanism that can be used to implement theexamples disclosed herein.

FIG. 3A shows a top view of an example valve that can be used to controlfluid flow through bleed ports of a compressor and/or a turbofan enginein accordance with the teachings of this disclosure.

FIG. 3B shows a cross-sectional view of the example valve of FIG. 3A.

FIG. 4 shows another top view of the example valve of FIG. 3A with thevalve in an intermediate position.

FIG. 5 shows example valves implemented on an example compressor inaccordance with the teachings of this disclosure.

FIG. 6 shows a detailed view of a first valve implemented on the examplecompressor of FIG. 5.

FIG. 7 shows example control rods coupled to the example valves wherethe control rods have positioned the valve to extract bleed air from the4^(th) stage of the compressor.

FIG. 8 shows the example control rods coupled to the example valveswhere the control rods have positioned the valve to extract bleed airfrom the 5^(th) stage of the compressor.

FIG. 9 shows an example actuator coupled to the control rods to actuatethe example valves between a first position and a second position.

FIG. 10 shows an example bleed band apparatus used to control fluid flowthrough bleed ports in accordance with the teachings of this disclosure.

FIG. 11 shows another example bleed band apparatus used to control fluidflow through bleed ports in accordance with the teachings of thisdisclosure.

FIG. 12 shows an example bleed band apparatus having a plug(s) used tocontrol fluid flow through bleed ports in accordance with the teachingsof this disclosure.

FIG. 13 is a flowchart that describes processes of implementing theexamples disclosed herein.

The figures are not to scale. Wherever possible, the same referencenumbers will be used throughout the drawing(s) and accompanying writtendescription to refer to the same or like parts.

DETAILED DESCRIPTION

Turbofan engines may include systems for bleeding air from the enginefor use by various aircraft systems (e.g., an environmental controlsystem (ECS)). Bleed air may be extracted after passing through thecompressor but prior to injecting fuel into the air. In multi-stagecompressors, bleed air may be taken from predetermined stages of thecompressor, such as, the 2^(nd) and 7^(th) stages. Existing engines maybe configured to bleed air from one or more predetermined stages priorto installation and/or use on the aircraft and are not easilyreconfigurable to change the bleed stage(s).

An advantage for using pressurized bleed air is the decrease in theloading of or need for air generators that may otherwise be needed toprovide air for cabin pressurization, anti-icing functionality, andothers. However, a disadvantage of bleed air is an overall reduction inthrust. To balance such competing interests, there may be a need forimproved systems which enable further control over the bleeding orextraction of air from the engine.

The examples disclosed herein relate generally to gas turbine engines(e.g., turbofan engines), which may enable substantial fuel burn savingsfor low occupant and/or other occupant level aircrafts. Moreparticularly, the examples disclosed herein relate to adjustable and/orincrementally adjustable bleed stage apparatuses and/or bleed portselection mechanisms for compressors of turbofan engines. Using theexamples disclosed herein, the performance of such engines may beincreased by selecting, tailoring and/or optimizing the bleed stageprior to and/or while operating the engine. Thus, using the disclosedexamples, a bleed stage can be adjusted and/or selected prior tooperating the engine without the relatively expensive reconfigurationassociated with some systems.

Example adjustable bleed stage apparatuses and/or bleed port selectionmechanisms according to the present disclosure may be incorporated intoany aircraft or other mobile platforms which uses, for example, a gasturbine as a power plant. For example, the aircraft may be a commercialtransport aircraft 100 as shown in FIG. 1. The aircraft 100 may includeone or more propulsion units (e.g., turbofan engines 110), which includean adjustable bleed stage apparatus and/or a bleed port selectionmechanism according to examples disclosed herein.

FIG. 2 shows a partial cross section of a turbofan engine 200 accordingto some examples disclosed herein. As described herein, a compressor 210of the turbofan engine 200 may include a low-pressure compressor at aforward portion of the turbofan engine 200 and a high-pressurecompressor 214 downstream of the low-pressure compressor with multiplerows or stages 220 comprising rotating blades and stator vanes. Thecompressor 210 may be enclosed within a housing or compressor case 230and a plenum 232 may be connected to the compressor case 230 to define aplenum cavity 252.

In the illustrated example of FIG. 2, the high-pressure compressor 214includes a 4^(th) stage associated with a first bleed port 302 that maybe used when the aircraft 100 has lower occupancy and a 5^(th) stageassociated with a second bleed port 304 that may be used when theaircraft 100 has higher occupancy. In some examples, as used herein,occupants of the aircraft 100 include people, passengers, crew, crewrests, cargo, heating and cooling systems, other options using enginebleed air, etc.

FIG. 2 also illustrates an example bleed port adjustment apparatusand/or a bleed port selection mechanism 250 according to the presentdisclosure. The bleed port selection mechanism 250 of the example ofFIG. 2 is positioned in the plenum cavity 252 and can be used to adjustand/or select a bleed stage for extracting bleed air from the compressor210 of the turbofan engine 200. In some examples, the bleed portselection mechanism 250 includes valves positioned at one or morecompressor stages (e.g., a fourth stage, a fifth stage, etc.) of theengine, as will be further described. In the illustrated examples, thevalves include first and second plates, a bleed band(s), sleeves and/orvalves that are movable relative to one another to enable more or lessfluid to flow through an aperture(s) and/or bleed aperture(s) defined bythe respective plates and/or the corresponding bleed ports. In someexamples, the plates are manually, automatically, linearly and/orrotatably movable relative to one another. In examples in which thebleed port selection mechanism 250 includes one or more bleed band(s),the bleed band may be moveable between a first position blocking a firstbleed port to a second position blocking a second bleed port. In someexamples, the bleed band may be moved to cover and/or not cover one ormore bleed ports of a stage (e.g., 4^(th) stage, 5^(th) stage) of thecompressor 210. To assist in moving and/or guiding the movement of thefirst and second plates, a bleed band(s), sleeves, etc. (e.g., portionsof the example valves), the example valves as disclosed herein mayinclude one or more guides, guide rails, etc.

In examples in which the bleed stage apparatus includes one or moreplates, for a particular stage, a desired bleed port flow path may beobtained by moving a first plate relative to a second plate to enableone or more first apertures of the first plate to be aligned and/orpositioned relative to corresponding second apertures of the secondplate. For example, coaxially aligning the first and second aperturesincreases the fluid flow through the apertures while off-setting thefirst and second apertures decreases the fluid flow through theapertures. In examples in which more than one set of plates areprovided, one of the first plates may be independently and/orsimultaneously movable and/or controllable relative to another one ofthe first plates.

FIGS. 3A and 3B illustrate different views of an example bleed portadjustment apparatus 400 that can be used to implement the bleed portselection mechanism 250 of FIG. 2. FIG. 3A illustrates a top partialview of the bleed port adjustment apparatus 400 and FIG. 3B shows afront and/or cross-sectional view of the bleed port adjustment apparatus400. The example bleed port adjustment apparatus 400 includes first andsecond concentric sleeves, cylinders and/or arched portions 402, 404.The first sleeve 402 may include one or more first apertures (e.g.,apertures 406, 408), and the second sleeve 404 may include one or moresecond apertures (e.g., apertures 410, 412). Any number of firstapertures and/or second apertures may be provided in the sleeves 402,404, respectively, along the radial direction or circumference of eachsleeve. The illustrations of the bleed port adjustment apparatus 400,including the size, shape, etc. of the aperture 406, 408, 410, 412, areprovided for illustration only and may not be to scale.

In some examples, the first apertures 406, 408 of the first sleeve 402may be in fluid communication with one or more bleed ports (e.g., thebleed port 302) formed in the compressor case 230. In some examples, thefirst sleeve 402 may be fixed and the second sleeve 404 may be movablerelative to the first sleeve 402. For example, the second sleeve 404 maybe radially slidable or rotatable about the first sleeve 402 and/orother fixed components of the turbofan engine 200 and/or the compressorcase 230. As shown in FIG. 3B, the bleed port adjustment apparatus 400may be coupled to an actuator 414 such as, for example, a hydraulicactuator, an electrical motor or any other suitable device toactuate/move the bleed port adjustment apparatus 400. In the illustratedexample, to adjust the positions of the apertures 406, 408 relative tothe apertures 410, 412, the actuator 414 moves and/or rotates the secondsleeve 404 relative to the first sleeve 402, e.g. via a control rod 416.

In operation, the second sleeve 404 may be movable from a first positionin which the second apertures 410, 412 are in fluid communication and/oraligned with the bleed ports 302 and/or 304 (e.g., fully open position)to a second position in which the second apertures 410, 412 are notfluidly coupled to and/or aligned with the bleed ports 302 and/or 304(e.g., fully closed position). The second sleeve 404 may be movable toany intermediate position to position the second apertures 410, 412between the fully open and fully closed positions. In further examples,the movable and stationary sleeves may be reversed such that the firstsleeve 402 is movable and the second sleeve 404 is fixed and adjustmentof the bleed stage is achieved by moving/rotating the first sleeve 402relative to the second sleeve 404 and/or other fixed components of theengine (e.g., the compressor casing). In such examples, the secondsleeve 404 may include one or more slots through which posts extend thatcouple the second sleeve 404 to the compressor case 230. Additionally oralternatively, in such examples, the second sleeve 404 may include aslot and/or aperture to enable the actuator 414 to couple to the firstsleeve 402 to enable the actuator 414 to move and/or rotate the firstsleeve 402 relative to the bleed ports 302 and/or 304. FIG. 4 shows theapertures 406, 408, 410, 412 of the sleeves 402, 404 at least partiallyaligning, thereby enabling fluid flow therethrough.

FIG. 5 shows an example turbofan engine 200 including a first valve 602and a second valve 604 that can be used to implement the bleed portselection mechanism 250 of FIG. 2. In the illustrated example, the firstvalve 602 includes first and second concentric arcs and/or sleeves 606,608 and the second valve 604 includes third and fourth concentric arcsand/or sleeves 610, 612. In some examples, the first sleeve 606 ismovable relative to the second sleeve 608 to enable fluid flow throughthe bleed port 302 and into the plenum cavity 252. In some examples, thethird sleeve 610 is movable relative to the fourth sleeve 612 to enablefluid flow through the bleed port 304 and into the plenum cavity 252. Insome examples, the valves 602, 604 include guides and/or rails to guidethe movement and/or rotation of the sleeves 606, 608, 610, 612.

FIG. 6 shows an enlarged view of the first valve 602. As shown, thefirst valve 602 includes the first and second concentric sleeves 606,608 that define apertures 702, 704 through which fluid flows when theapertures 702, 704 are aligned. FIG. 6 also shows a seal(s) 706positioned between the sleeves 606, 608 and on either side of theapertures 702, 704 that substantially prevents fluid flow between thefirst and second concentric sleeves 606, 608. In the illustratedexample, the seal 706 is a labyrinth seal. However, in other examples,the seal 706 may be any other suitable seal.

FIG. 7 shows control rods and/or linkage 802, 804, 806 coupled to thesleeves 608, 612 to move (e.g., simultaneously move and/or control) thesleeves 608, 612 to change an amount of fluid flow through theassociated apertures and/or bleed ports 302, 304. In the illustratedexample, the control rods 802, 804, 806 have moved the second sleeve 608to enable fluid flow through the bleed port 304 corresponding to afourth stage of the compressor 210 and have moved the fourth sleeve 612to substantially stop fluid flow through the bleed port 302corresponding to a fifth stage of the compressor 210. In some examples,the control rods 802, 804, 806 pivot about a pivot point 808 and can belocked in a particular position using locks and/or locking mechanism(s)810, 812. FIG. 7 shows the sleeves 608, 612 in a position correspondingto a 4^(th) stage of the compressor 210 and FIG. 8 shows the sleeves608, 612 in a position corresponding to a 5^(th) stage of the compressor210. FIG. 9 shows the control rods 802, 804, 806 being actuated by anactuator 1002 that enables the position of the sleeves 608, 612 to beautomatically adjusted. For example, the actuator 1002 may automaticallyadjust the sleeves 608, 612 while the engine 200 is running or prior tooperating the engine 200.

In other examples and as shown in FIGS. 10, 11 and 12, the bleed portselection mechanism 250 is implemented as an example bleed band 1102(e.g., belly band) positioned over one or more bleed ports 302, 304 toblock and/or at least partially block the fluid flow through therespective bleed ports 302, 304. In some examples, the bleed band 1102is movable down a length of a housing of a compressor to at leastpartially the block bleed port(s) 302, 304 at a particular stage (e.g.,the 4^(th) stage). In some such examples, the bleed band 1102 is movableby loosening and/or relaxing the bleed band 1102 and thereafter movingthe bleed band 1102 from a first position 1104 corresponding to a fourthstage of the compressor to a second position 1106 corresponding to afifth stage of the compressor. Additionally or alternatively, exampleguides and/or guide bands may be provided to guide the movement of thebands relative to the compressor housing. Additionally or alternatively,in some examples, the bleed bands include discreet plugs and/orprotrusions that align with compressor case holes to smooth thecompressor flowpath and/or substantially eliminate and/or reducedisturbances generated by steps in the flowpath.

FIG. 10 shows the example compressor 210 and an example bleed band 1102that can be used to implement the bleed port selection mechanism 250 ofFIG. 2. The example bleed band 1102 can be moved between a firstposition and/or first location 1104 and a second position and/or secondlocation 1106 using a slotted guide 1107. Depending on the position ofthe bleed band 1102, the bleed band 1102 controls fluid flow through thebleed ports 302, 304. To move the bleed band 1102 from the firstposition 1104, an operator may loosen the bleed band 1102 and move thebleed band 1102 through the guide 1107 until the bleed band 1102 ispositioned adjacent the second bleed port 304. Once at the secondposition, the operator may tighten the bleed band 1102 about thecompressor case 230.

FIG. 11 shows an example bleed band 1200 that can be used to implementthe bleed port selection mechanism 250 of FIG. 2. FIG. 11 shows theexample bleed band 1200 covering apertures 1202, 1204, 1206, 1208, 1210.FIG. 11 also shows an apparatus, regulator, actuator and/or valve 1212used to control the position of the bleed band 1200. In the illustratedexample, the apparatus 1212 includes a spring biased piston 1214 havinga stem 1216 that is coupled to an end 1218 of the bleed band 1200.Moving the piston 1214 in a first direction generally indicated by arrow1220 moves the bleed band 1200 away from a compressor 1221 andincrementally moves the bleed band 1200 from covering the apertures1202, 1204, 1206, 1208, 1210. Having the bleed band not cover and/or todisposed at a distance from one or more of the apertures 1202, 1204,1206, 1208, 1210 allows air flow and/or more air flow through therespective apertures 1202, 1204, 1206, 1208, 1210. Moving the piston1214 in a second direction generally indicated by arrow 1222 moves thebleed band 1200 towards the compressor 1221 and incrementally moves thebleed band 1200 to cover the apertures 1202, 1204, 1206, 1208, 1210.Having the bleed band 1200 cover one or more of the apertures 1202,1204, 1206, 1208, 1210 limits and/or prevents airflow through therespective apertures 1202, 1204, 1206, 1208, 1210.

FIG. 12 shows an example bleed band 1300 that can be used to implementthe bleed port selection mechanism 250 of FIG. 2. In this example, thebleed band 1300 includes a plug and/or protrusion 1302 aligned with acompressor case hole 1304 to smooth the compressor flowpath and/orsubstantially eliminate and/or reduce flow disturbances generated bysteps in the flowpath.

FIG. 13 is a flow diagram representative of example operations (e.g.,manual operations) that can be executed to implement the teachings ofthis disclosure. The example operations of FIG. 13 can be implementedusing, for example, the bleed port adjustment apparatus 400, the valves602, 604 and/or the bleed band 1102, 1200, 1300. While an example mannerof implementing the examples disclosed herein is illustrated in FIG. 13,one or more of the elements, processes and/or devices illustrated inFIG. 13 may be combined, divided, re-arranged, omitted, eliminatedand/or implemented in any other way.

The process of FIG. 13 begins at block 1402 where an instruction isreceived to extract bleed air from a first stage of a compressor and/oran engine (block 1402). In some examples, to enable bleed air to beextracted from the first stage, the first valve is adjusted (block1404). In some examples, to enable bleed air to be extracted from thefirst stage, the second valve is adjusted (block 1406). For example, toadjust either of the first and/or second valves 602, 604, the firstand/or second sleeves 402, 404, 606, 608, 610, 612 can be moved relativeto the apertures 406, 408, 410, 412 and/or bleed ports 302, 304 toenable fluid flow through one or more apertures 406, 408, 410, 412 andsubstantially prevent fluid flow through one or more of the otherapertures 406, 408, 410, 412. After the valves are in position, thebleed air may be extracted from the first stage of the compressor (block1408).

At block 1410, it is determined whether or not to extract bleed air froma second stage of the compressor and/or the engine (block 1410). If aninstruction is received to extract bleed air from the second stage, thefirst valve is adjusted (block 1412). If an instruction is received toextract bleed air from the second stage, the second valve is adjusted(block 1414). After the valves are in position, the bleed air may beextracted from the second stage of the compressor (block 1416). Whilethis example describes adjusting first and second valves, in otherexample, a single valve implemented as a bleed band may be used and/ormoved to control fluid flow through the bleed ports associated with thefirst and second stages.

The examples disclosed herein enable an engine bleed to be extractedfrom one of two high pressure configurations. In some examples, thebleed stage may be selected manually prior to operating the engineand/or automatically while the engine is operating at idle. In someexamples, the disclosed examples enable an engine to be configured tosubstantially match airplane environment control system requirementswith substantially no impact on an engine airplane interface.

In some examples, using the examples disclosed herein, a lower moreenergy efficient compressor stage can be selected for an aircraft havinga relatively low occupant count and a higher compressor stage can beselected for an aircraft with a higher equivalent occupant count.

Using the disclosed examples, an operator and/or mechanic can select thebleed stage prior to flight based on, for example, the number ofpassengers, crew rests, heating and/or cooling systems, other areasrequiring engine bleed air, etc. In some examples, the same plenum canbe used for different bleed stages because the bleed port adjustmentapparatus can control the fluid flow through the different stages andthe plenum is positioned on the stages. In some examples, the examplesdisclosed herein enable one stage (e.g., a fourth stage) of thecompressor to be opened up to the plenum and another stage (e.g., afifth stage) of the compressor to be isolated and/or closed off from theplenum. In some examples, engines can be produced including the examplesdisclosed herein to improve performance and provide a greater number ofoptions.

In some examples, a high pressure compressor (HPC) low stage bleed portis the lowest stage that meets airplane pressure requirements during acruise phase of a mission for all equivalent occupant counts. In someexamples, the optimum and/or preferred stage is between two stages. Insuch examples, the higher stage is typically selected resulting in afuel burn penalty for airlines that order airplanes with low equivalentoccupant counts. The examples disclosed herein enable an operator and/ora mechanic to manually and/or automatically configure the bleed port(s)to, for example, a fourth stage and a fifth stage. Thus, the examplesdisclosed herein improve engine performance by allowing customers/usersto select the optimum bleed stage as opposed to an otherwise moreconservative stage that would meet airplane bleed requirements of theparticular aircraft.

From the foregoing, it will appreciated that the above disclosed methodsand apparatus relate to selecting a bleed stage for a high pressurecompressor of a turbofan engine where the apparatus is configured toenable selection of a bleed stage without replacement of the bleedplenum and/or off takes of the engine bleed system. In some examples,and as described in connection with FIGS. 7-9, the apparatus is furtherconfigured to actuate one bleed stage OFF responsive to actuatinganother bleed stage ON.

As set forth herein, an example apparatus for bleeding air from amulti-stage compressor of an aircraft engine is disclosed. The exampleapparatus includes a compressor case including a plurality of bleedports. A first bleed port is associated with a first stage of acompressor, and a second bleed port associated with a second stage ofthe compressor. The example apparatus includes a plenum connected to thecompressor case to define a plenum cavity. The plenum fluidly couplingthe first and second bleed ports to a fluid conduit for providing bleedair to one or more systems of an aircraft. The example apparatusincludes a bleed port selection mechanism located within the plenumcavity. The bleed port selection mechanism includes a first portionproximate the first bleed port and operable to prevent fluid flowthrough the first bleed port.

In some examples, the bleed port selection mechanism also includes asecond portion proximate the second bleed port and operable to preventfluid flow through the second bleed port. In some examples, at least oneof the first portion or the second portion includes a sleeve, where thesleeve includes an aperture movable relative to the compressor case. Insome examples, at least one of the first portion or the second portionincludes a pair of concentric sleeves. A first sleeve of the pair ofconcentric sleeves is movable relative to a respective bleed portassociated therewith and the second sleeve of the pair of concentricsleeves is stationary relative to the respective bleed port. In someexamples, the apparatus also includes a seal between the first sleeveand the second sleeve to substantially prevent fluid flow between thefirst sleeve and the second sleeve. In some examples, the seal includesa labyrinth seal.

In some examples, the apparatus also includes an actuator associatedwith at least one of the first portion or the second portion. Theactuator is configured to move the at least one of the first portion andthe second portion relative to respective one of the first bleed port orthe second bleed port. In some examples, the first portion iscontrollable independently from the second portion. In some examples,the apparatus also includes a linkage coupled to the first portion andto the second portion to enable substantially simultaneous control ofthe first portion and the second portion.

In some examples, the apparatus also includes a locking mechanism tosecure the linkage in a position. In some examples, the first portion ismovable between a first position in which the first portion isassociated with the first bleed port to a second position in which thefirst portion is associated with the second bleed port. In someexamples, the apparatus includes a guide between the first position andthe second position.

Another example apparatus includes a compressor of a turbofan engine.The compressor includes a compressor case including a first aperture.The apparatus also includes a bleed band including a first end and asecond end. The bleed band is to at least partially surround thecompressor case. The apparatus also includes an actuator coupled to thefirst end of the bleed band. The actuator is to move the first endbetween a first position in which the bleed band at least partiallycovers the first aperture to substantially prevent fluid flow throughthe first aperture to a second position in which the bleed band isdisposed a distance apart from the first aperture to enable fluid flowthrough the first aperture.

In some examples, the bleed band also includes a protrusion configuredto be received in the first aperture when the bleed band is in the firstposition. In some examples, the first aperture is associated with one ofa plurality of stages of the compressor. The compressor case includes asecond aperture associated with another one of the plurality of stagesof the compressor. The bleed band is movable between a first locationassociated with the first aperture to a second location associated withthe second aperture.

An example method for selecting a bleed stage of an engine of anaircraft is disclosed. The example method includes flowing fluid througha compressor of the engine. The compressor includes a first compressorstage, a second compressor stage, a compressor case surrounding thecompressor and first and second bleed ports associated with the firstand second compressor stages, respectively. The method also includesbleeding at least a portion of said fluid through the first bleed portor the second bleed port into a plenum fluidly coupling the first andsecond bleed ports to a system of the aircraft. The method also includesactuating a bleed port selection mechanism disposed within the plenum toat least partially prevent fluid flow through one of the first bleedport or the second bleed port without affecting fluid flow through theother one of the first bleed port or the second bleed port.

In some examples, the bleed port selection mechanism includes a firstvalve associated with the first bleed port. Actuating the bleed portselection mechanism includes moving a first aperture of the first valveout of alignment with the first bleed port. In some examples, the bleedport selection mechanism also includes a second valve associated withthe second bleed port. Actuating the bleed port selection mechanism alsoincludes moving the first aperture into alignment with the first bleedport and covering the second bleed port with the second valve. In someexample, actuating the bleed port selection mechanism occurs while theengine is idling. In some examples, the bleed port selection mechanismincludes a sleeve. Actuating the bleed port selection mechanism includesmoving the sleeve between a first location in which the sleeve coversthe first bleed port and a second location in which the sleeve coversthe second bleed port.

Although certain example methods, apparatus and articles of manufacturehave been disclosed herein, the scope of coverage of this patent is notlimited thereto. On the contrary, this patent covers all methods,apparatus and articles of manufacture fairly falling within the scope ofthe claims of this patent.

The invention claimed is:
 1. A method to extract bleed air from anaircraft engine, the method comprising: extracting, via a plenumpositioned in a compressor of the aircraft engine, bleed air from afirst bleed port associated with a first stage of a compressor and asecond bleed port associated with a second stage of the compressor, theplenum configured to combine the extracted bleed air from the first andsecond bleed ports and fluidly couple the extracted bleed air to one ormore systems of an aircraft; and regulating a pressure of the extractedbleed air in the plenum by adjusting a flow of bleed air through thefirst bleed port via a first valve associated with the first bleed portand adjusting a flow of bleed air through the second port via a secondvalve associated with the second bleed port, the first valve including afirst pair of sleeves and the second valve including a second pair ofsleeves, and the regulating of the pressure of the extracted bleed airincludes moving at least one of the first pair of sleeves to control theflow of bleed air through the first bleed port or the second pair ofsleeves to control the flow of bleed air through the second bleed port.2. The method of claim 1, further including controlling the first valveand the second valve simultaneously to adjust the flow of bleed airthrough the respective first and second bleed ports to regulate thepressure of the extracted bleed air in the plenum.
 3. The method ofclaim 1, further including controlling the first valve independentlyrelative to the second valve to adjust the flow of bleed air through therespective first and second bleed ports to regulate the pressure of theextracted bleed air in the plenum.
 4. The method of claim 1, wherein thefirst stage provides bleed air having a first pressure and the secondstage provides bleed air having a second pressure, the second pressurebeing greater than the first pressure, and wherein regulating thepressure of the extracted bleed air includes regulating the pressuresuch that pressure of the extracted bleed air within the plenum isbetween the first pressure and the second pressure.
 5. The method ofclaim 1, wherein regulating the pressure of the extracted bleed air inthe plenum occurs during operation of the aircraft engine.
 6. The methodof claim 1, wherein the first stage provides bleed air having a firstpressure and the second stage provides bleed air having a secondpressure, the second pressure being higher than the first pressure, andfurther including moving the first valve towards a closed position torestrict bleed air from the first bleed port to the plenum andsimultaneously moving the second valve towards an open position to allowbleed air from the second bleed port to the plenum to increase thepressure of the extracted bleed air in the plenum.
 7. An apparatus forbleeding air from a multi-stage compressor of an aircraft engine, theapparatus comprising: a compressor including a first bleed port and asecond bleed port, wherein the first bleed port is associated with afirst stage of a compressor and a second bleed port is associated with asecond stage of the compressor; a fluid conduit to channel bleed airfrom at least one of the first bleed port or the second bleed port toone or more systems of an aircraft; a bleed port selection mechanismproximate the first bleed port and the second bleed port, the bleed portselection mechanism including a first valve having a first pair ofsleeves associated with the first bleed port to control fluid flow fromthe first bleed port to the fluid conduit, and a second valve having asecond pair of sleeves associated with the second bleed port to controlfluid flow from the second bleed port to the fluid conduit; and acontrol system configured to: extract bleed air from at least one of thefirst bleed port associated with the first stage of the compressor orthe second bleed port associated with the second stage of the compressorvia the bleed port selection mechanism, the bleed port selectionmechanism configured to combine the extracted bleed air from the firstand second bleed ports; and regulate a pressure of the extracted bleedair by adjusting a flow of bleed air through the first bleed port andthe second port, wherein the adjusting of the flow of bleed air throughthe first bleed port and the second bleed port includes moving at leastone of the first pair of sleeves to control a flow of bleed air throughthe first bleed port or the second pair of sleeves to control a flow ofbleed air through the second bleed port.
 8. The apparatus of claim 7,wherein the first pair of sleeves includes a first sleeve and a secondsleeve, the first sleeve being concentric relative to the second sleeve,and wherein the first sleeve includes a first aperture and the secondsleeve includes a second aperture.
 9. The apparatus of claim 8, whereinthe first sleeve is to move relative to the second sleeve between afirst position at which the first aperture and the second aperture alignto enable fluid flow from the first bleed port to the fluid conduit, anda second position at which the first aperture is not aligned with atleast one of the second aperture or an outlet of the first bleed port torestrict fluid flow from the first bleed port to the fluid conduit. 10.The apparatus of claim 7, wherein the second pair of sleeves includes athird sleeve and a fourth sleeve, the third sleeve being concentricrelative to the fourth sleeve, and wherein the third sleeve includes athird aperture and the fourth sleeve includes a fourth aperture.
 11. Theapparatus of claim 10, wherein the third sleeve is to move relative tothe fourth sleeve between a first position at which the third apertureand the fourth aperture align to enable fluid flow from the second bleedport to the fluid conduit, and a second position at which the thirdaperture is not aligned with at least one of the fourth aperture or anoutlet of the second bleed port to restrict fluid flow from the secondbleed port to the fluid conduit.
 12. The apparatus of claim 7, furthercomprising an actuator associated with at least one of the first pair ofsleeves or the second pair of sleeves, the actuator configured to movethe at least one of the first pair of sleeves or the second pair ofsleeves relative to the first bleed port or the second bleed port,respectively.
 13. The apparatus of claim 7, wherein the first pair ofsleeves is controllable independently from the second pair of sleeves.14. The apparatus of claim 7, further comprising a linkage assemblycoupled to the first pair of sleeves and the second pair of sleeves toenable simultaneous control of the first pair of sleeves and the secondpair of sleeves.
 15. An apparatus, comprising: a compressor caseincluding a first bleed port associated with a first stage of acompressor and a second bleed port associated with a second stage of thecompressor; a plenum connected to the compressor case to define a plenumcavity, the plenum fluidly coupling the first and second bleed ports toa fluid conduit to provide bleed air to one or more systems of anaircraft; and a bleed port selection mechanism located within the plenumcavity, the bleed port selection mechanism including a first valveassociated with the first bleed port and a second valve associated withthe second bleed port, the first valve including a first sleeve and asecond sleeve, the first sleeve having a first aperture and the secondsleeve having a second aperture, the bleed port selection mechanism isto move at least one of the first sleeve or the second sleeve relativeto the other one of the first sleeve of the second sleeve between: afirst position to align the first aperture and the second aperture,alignment of the first aperture and the second aperture to provide afirst flow path to allow bleed air to flow from the first bleed port tothe plenum cavity; a second position to offset the first aperturerelative to the second aperture to block the first flow path to preventflow of bleed air from the first bleed port to the plenum cavity; acontrol system configured to: extract bleed air from at least one of thefirst bleed port associated with the first stage of the secondcompressor or the second bleed port associated with the second stage ofthe compressor via the bleed port selection mechanism, the bleed portselection mechanism configured to combine the extracted bleed air fromthe first and second bleed ports; and regulate a pressure of theextracted bleed air in the plenum by adjusting a flow of bleed airthrough the first bleed port via the first valve associated with thefirst bleed port and adjusting a flow of bleed air through the secondport via the second valve associated with the second bleed port, whereinthe adjusting of the flow of bleed air through the first bleed port viathe first valve includes moving the at least the first sleeve or thesecond sleeve relative to the other one of the first sleeve or thesecond sleeve.
 16. The apparatus of claim 15, further including a firstactuator operatively coupled to at least one of the first sleeve or thesecond sleeve and controllable via the control system, the firstactuator to move the at least the first sleeve or the second sleeverelative to the other one of the first sleeve or the second sleeve tocause the first aperture to align with the second aperture.
 17. Theapparatus of claim 15, wherein the second valve including a third sleeveand a fourth sleeve, the third sleeve having a third aperture and thefourth sleeve having a fourth aperture, the bleed port selectionmechanism is to move at least one of the third sleeve or the fourthsleeve relative to the other one of the third sleeve of the fourthsleeve between: a third position to align the third aperture and thefourth aperture, alignment of the third aperture and the fourth apertureto provide a second flow path to fluidly couple bleed air to flow fromthe second bleed port to the plenum cavity; and a fourth position tooffset the third aperture relative to the fourth aperture to block thesecond flow path to prevent flow of bleed air from the second bleed portto the plenum cavity.
 18. The apparatus of claim 17, wherein the controlsystem is configured to move the at least the third sleeve or the fourthsleeve relative to the other one of the third sleeve or the fourthsleeve to regulate a pressure of the bleed air in the plenum byadjusting a flow of bleed air through the second bleed port via thesecond valve associated with the second bleed port.
 19. The apparatus ofclaim 18, further including an actuator operatively coupled to the firstvalve and the second valve and controllable via the control system, theactuator to move the at least one of the first sleeve or the secondsleeve relative to the other one of the first sleeve or the secondsleeve and at least one of the third sleeve or the fourth sleeverelative to the other one of the third sleeve or the fourth sleeve toregulate the pressure of the bleed air in the plenum.
 20. The apparatusof claim 19, wherein the actuator is operatively coupled to the at leastone of the first sleeve or the second sleeve via a first linkage and theat least one of the third sleeve and the fourth sleeve via a secondlinkage, and further including a third linkage to operatively couple thefirst linkage and the second linkage.